Prepared in cooperation with the Pennsylvania Department of Environmental Protection

By Dennis J. Low, Douglas C. Chichester, and Linda F. Zarr

Abstract

This study, by the U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Environmental
Protection
(PADEP), provides a compilation of ground-water-quality data for a 28-year period (January 1, 1979, through December 31, 2006) based
on water samples from wells and springs. The data are from 14 source agencies or programs—Borough of Carroll Valley, Chester
County Health Department, Montgomery County Health Department, Pennsylvania Department of Agriculture, Pennsylvania Department of
Environmental Protection 2002 Pennsylvania Water-Quality Assessment, Pennsylvania Department of Environmental Protection Agency
Act 537 Sewage Facilities Program, Pennsylvania Department of Environmental Protection-Ambient and Fixed Station Network, Pennsylvania
Department of Environmental Protection–North-Central Region, Pennsylvania Department of Environmental Protection–South-Central Region, Pennsylvania Drinking Water Information System, Pennsylvania Topographic and Geologic Survey, Susquehanna
River Basin Commission, U.S. Environmental Protection Agency, and the U.S. Geological Survey. The ground-water-quality data from the
different source agencies or programs varied in type and number of analyses; however, the analyses are represented by 11 major analyte
groups: antibiotics, major ions, microorganisms (bacteria, viruses, and other microorganisms), minor ions (including trace elements),
nutrients (predominantly nitrate and nitrite as nitrogen), pesticides, pharmaceuticals, radiochemicals (predominantly radon or radium), volatiles (volatile organic compounds), wastewater compounds, and water characteristics (field measurements, predominantly field pH, field specific conductance, and hardness).
For the USGS and the PADEP–North-Central Region, the pesticide analyte group was broken down into fungicides, herbicides, and
insecticides.

Summary maps show the areal distribution of wells and springs with ground-water-quality data statewide by source agency or program.
Summary data tables by source agency or program provide information on the number of wells and springs and samples collected for each
of the 35 watersheds and analyte groups.

The number of wells and springs sampled for ground-water-quality data varies considerably across Pennsylvania. Of the 24,772 wells and
springs sampled, the greatest concentration of wells and springs is in the southeast (Berks, Bucks, Chester, Delaware, Lancaster,
Montgomery, and Philadelphia Counties) and in the northwest (Erie County). The number of wells and springs sampled is relatively sparse in north-central (Cameron, Elk, Forest, McKean, Potter, and Warren Counties)
Pennsylvania. Little to no data are available for approximately one-fourth of the state. Nutrients and water characteristics
were the most frequently sampled major analyte groups—43,025 and 30,583 samples, respectively. Minor ions and major ions were the next most frequently sampled major analyte groups–26,972 and 13,115 samples, respectively. For the remaining 10 major analyte groups, the number of samples collected ranged from a low of 24 samples (antibiotic compounds)
to a high of approximately 4,674 samples (microorganisms).

If you have Adobe® Acrobat® or Adobe® Acrobat®Reader® installed on your computer, you may view and print the PDF version
of this report. Acrobat Reader, is a free download from Adobe
Systems Incorporated.